Mesophiles (medium-temperature microbes)

Mesophiles (中温菌, chuonkin) are microorganisms whose optimal growth temperature falls in the range of 25 to 35°C. In sake brewing, mesophiles play a particularly important role, helping the fermentation process proceed smoothly. Lactic acid bacteria and acetic acid bacteria are examples of microbes in this temperature range, and they influence the flavor and aroma of sake. By contrast, microbes with an optimal temperature of 10 to 20°C are called psychrophiles (low-temperature microbes), and those with an optimal temperature of 40°C or higher are called thermophiles (high-temperature microbes); each has different characteristics. Mesophiles contribute to improving sake quality and to the stability of fermentation, and their balance with other types of microbes is one of the factors that shape the taste of sake.